Mobile pneumatic granular material conveying systems are used to unload and transport granular materials from vehicles, such as railcars, barges, and ship holds, to storage silos and factories. G. V. Aalst in U.S. Pat. No. 4,659,262 describes such a mobile pneumatic granular material conveying system having an articulated vacuum arm supporting a hose for carrying material from an intake nozzle to a material storage tank. An operator located near the material storage structure uses a remote control device to position the vacuum arm to locate the nozzle in the material so that the material is drawn into the hose and transported to a storage tank. A vacuum machine and boom mounted on a motor truck is disclosed by H. J. Davis in U.S. Pat. No. 5,142,732. The boom supports a material pick up hose and a bulk material separator operable to remove heavy bulk materials without materially reducing the vacuum in the hose. These vacuum conveying and boom structures do not allow the work person to be positioned in the chamber or space being cleaned during the cleaning process. The work person is not in a position that allows for visual inspection of the chamber and movement of the material pick up hose to a location to effectively and efficiently remove particulate materials from the chamber of a railcar or container. Railcars have bottom gates that allow the bulk load carried by the railcar to be unload by allowing the load to flow down. Residual load or particulate materials adhere to the walls of the railcar or remain in the chamber of the railcar. The residual particulate material are removed from the chamber of the railcar with the vacuum cleaning apparatus of the invention.